1. Field of the Invention
The invention relates to a fixation element for an implantable microphone, which element is adapted to be inserted into a bore which crosses a wall of the auditory canal of a user.
2. Description of Related Art
Such a fixation element is known e.g. from U.S. Pat. No. 5,999,632. The known fixation element comprises a cylindrical portion which surrounds an outer circumferential portion of a housing part of the microphone. This housing part is provided with a sound receiving member of the microphone, particularly an acoustic membrane, which is left uncovered by the fixation element. Projecting elastic flange portions are provided at the side of the cylindrical portion which, in the implanted state of the fixation element, faces the skin of the auditory canal. In the implanted state of the fixation element, these flange portions contact the respective side of the wall of the auditory canal. A further flange portion is provided at the side of the cylindrical portion which, in the implanted state of the fixation element, is remote from the skin of the auditory canal, and this further flange portion is adapted to contact the other side of the wall of the auditory canal. The flange portions and the cylindrical portion define a sleeve by which the microphone is fixed in the wall of the auditory canal. The cylindrical portion has a smooth outer side for contacting the wall of the bore.
International Patent Application Publication WO-A 97/36457 discloses a fixation element for fixing a microactuator of an implantable hearing systems in a bore in the promontorium wherein sleeve portion is inserted into the bore, and wherein this sleeve portion is provided at one end thereof with a circumferentially extending projecting flange which contacts one side of the promontorium. The part of the sleeve portion disposed within the bore is hollow-cylindrical and has a smooth outer surface. At the end opposite the flanged end, the hollow-cylindrical portion is provided with zone within which the inner and outer diameters of the hollow-cylindrical portion conically increase. The cylindrical microactuator is inserted into the sleeve portion from the flanged side thereof and is locked by lock means provided on the flange.